Geographic Variation of A-Superfamily Venom Peptides in Conus Catus
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Conus catus is a venomous fish-hunting cone snail. This marine snail uses an extremely rapid prey-capture mechanism that involves extending its proboscis, quickly shooting its radular tooth into the fish, and injecting venom through the tooth into its prey. One major group of venom peptide encoding sequences is the A-superfamily, which includes α-conotoxins and neuroexcitatory peptides. α-Conotoxins inhibit acetylcholine receptors and cause flaccid paralysis while neuroexcitatory peptides cause tetanic paralysis. Neuroexcitatory peptides are the most active components in C. catus venom, and their molecular target is currently under investigation. By comparing mature toxin sequences from Samoan C. catus to those from Hawaiian C. catus , we can determine whether geographic variation of the venom peptide encoding sequences exists in this species. A-superfamily encoding genes were amplified from Samoan C. catus genomic DNA, and were then cloned and sequenced. After looking at 128 sequences, I found 3 α-conotoxins in common with Hawaiian C. catus and one novel α-conotoxin not found in Hawaiian C. catus . In addition, I have found 2 neuroexcitatory peptides that are also in Hawaiian C C. catus , and one neuroexcitatory peptide not found in Hawaiian C. catus . I have also found support for a new subfamily of neuroexcitatory peptides. This data suggests that there is geographic variation in the venom peptide encoding sequences in C. catus , thus there could exist a greater number of biologically active peptides that we could study to use for therapeutic purposes or reagents for basic biology research.